There are two ways to send an immediate test without waiting for the delay periods:

Using the Send Test Email(s) button the Cart Layout page sends all of the stages of the trigger you have selected using the cart layout you have selected.

For example, if you have a three stage cart abandonment trigger, each using a different layout (Layout 1 for stage 1, Layout 2 for stage 2, and so on) and you are currently looking at Layout 1, when you do a test send you receive three emails, each with Layout 1 used for the cart layout.

Learn more in Test a trigger.